1. Field of the Invention
This invention relates to fixing means for connecting components, particularly prefabricated concrete members or tubbing stones, which means comprises a plurality of pluglike anchors adapted to be forced with elastic deformation into anchor holes formed in said components and open in facing surfaces of said components, so that the anchors are frictionally held in and/or positively locked in the anchor holes.
2. Description of the Prior Art
Fixing means of that kind are used, e.g., in the construction of tunnel linings, to connect the tubbing stones or other ring elements, and may be substituted for conventional screw fasteners, which are expensive and can be used only with difficulty and involve a weakening of the material. The anchors may be mounted before a new stone is installed so that the anchors may be used also to align an additional component with previously placed components so that a modular assembly of the components can be obtained. Other fields of application of fixing means of the present kind are joints between relatively large structural components, such as prefabricated concrete elements, in building construction and civil engineering.
From EP-A-100 771 it is known to connect tubbing stones by means of sleevelike liners, which are inserted into anchor holes and made of rubber-elastic or other elastically deformable material and have holes which flare conically near and toward the outer end of the sleeve but are cylindrical elsewhere. Anchors are employed which consist of cylindrical metal rods, which have pointed ends and are first driven into the anchor holes of one stone and as the stones are engaged with each other are inserted into the liners of the previously placed stone. The inside diameter of the cylindrical holes of the liners is smaller than the outside diameter of the metal rods so that said metal rods are inserted into the liners with elastic deformation and are frictionally retained therein. The elastic deformability of the sleevelike liners is intended to effect a correction of any misalignment of the axes of the metal rods and the axes of the associated anchor holes.
DE-A-22 38 792 provides for connecting platelike segments by fixing means which consist of sleeves, which are inserted into one component, and anchor bolts, which are fixed to the other component. Spring tongues are secured to the sleeve and protrude from the open free end of the sleeve. Said spring tongues are deflected and clamp the bolt as it is inserted into the sleeve so that a frictional contact is achieved. EP-A-114 514 discloses similar fixing means for connecting tubbing stones.
DE-A-24 57 427 discloses fixing means which are of the kind described first hereinbefore and comprise an anchor consisting of a steel bolt having in cross-section a sawtoothlike external shape but uniform crest and root diameters. That steel bolt is adapted to be forced into a liner, which has been inserted into the anchor hole and is made of rubber-elastic material and has on the outside a mating or corrugated shape in cross-section.
All these fixing means have the disadvantage that separate liners made, e.g., of rubber-elastic material must be inserted into the anchor holes so that the manufacture of the components is difficult. If the anchor and the liner in the anchor hole have corresponding shapes in cross-section, the restraining force will not be sufficiently large and from the beginning of the insertion of the anchor into the liner it is necessary to overcome the resistance of the liner to deformation until the anchor has been inserted as far as is required. In some designs that resistance to deformation progressively increases as that insertion proceeds. Particularly at the beginning of the insertion the anchor will be subjected to a high buckling load and this must be taken into account in the selection of the cross-sectional areas. Where fixing means which establish only a restraining frictional engagement are employed, the driving forces required and the restraining forces will not exactly be defined owing to the manufacturing tolerances. Similar remarks are applicable for a fixation by means of deflectable spring tongues.